The exemplary embodiments of the inventive concept described herein relate to a storage system, and more particularly, relate to a storage system capable of managing run-time bad cells.
A storage system includes a host and a storage device. The host and the storage device are connected through a variety of standardized interfaces, such as a serial AT Attachment (SATA), universal flash storage (UFS), a small computer small interface (SCSI), a serial attached SCSI (SAS), and an embedded multi-media controller (eMMC).
A storage device contains a nonvolatile memory and a device memory. The nonvolatile memory may include the following: flash memory, electrically erasable programmable read-only memory (EEPROM), magnetoresistive random-access memory (MRAM), phase-change memory (PRAM), and ferroelectric random-access memory (FeRAM). The device memory is used to temporarily store data to be written at the nonvolatile memory or data read out from the nonvolatile memory. The device memory may be implemented with a volatile memory or a nonvolatile memory. The device memory may include the following: dynamic random-access memory (DRAM), static random-access memory (SRAM), MRAM, PRAM, and FeRAM.
The nonvolatile memory or the device memory includes a plurality of memory cells. In the nonvolatile memory or the device memory, a defect may happen at memory cells when fabricated or used. Below, the defective memory cell is referred to as a bad cell. Bad cells that occur when fabricated are easily searched by testing the whole memory area. However, it is difficult to search bad cells that occur when a product including the memory cells is used.